✨ Features: TypeScript interfaces & types, Zod schemas, Python dataclasses, Go structs — nested objects, arrays, union types, automatic type inference
export interface Root {
user: {
id: number;
name: string;
email: string;
isActive: boolean;
roles: string[];
metadata: {
lastLogin: string;
loginCount: number;
};
};
posts: ({
id: number;
title: string;
tags: string[];
})[];
}Showing 8 of 94 related tools
Get up and running in 30 seconds
Copy JSON from API responses, database queries, or any data source and paste into the input field. The tool analyzes structure and infers TypeScript types from values.
Choose interface or type alias syntax. Enable optional properties (?:) for nullable fields. Select strict or loose type inference based on your needs.
See TypeScript interfaces generated from JSON structure. Nested objects become nested interfaces. Arrays infer element types. Property names are validated as valid TypeScript identifiers.
Click Copy to grab TypeScript code. Paste into .ts files in your project. Use generated types for type-safe API calls, state management, or data validation.
Understanding JSON to TypeScript generation
JSON to TypeScript conversion generates TypeScript interface definitions from JSON data structures, enabling type-safe development when working with APIs, databases, and external data sources. Instead of manually writing types for API responses, this tool infers types automatically from example JSON, saving hours of work and reducing type definition errors.
TypeScript requires explicit type definitions for objects to provide compile-time safety and IntelliSense autocomplete. When integrating REST APIs, GraphQL endpoints, or database queries that return JSON, developers need TypeScript interfaces matching the response structure. Manually creating these interfaces is tedious, error-prone (missing properties, wrong types), and becomes outdated when APIs change.
Accelerate API Integration: Fetch an API response, paste JSON, get TypeScript types instantly. No manual interface writing. Paste the generated interface into your codebase and TypeScript validates all API usage immediately.
Ensure Type Accuracy: Human-written types often have mistakes - wrong property types, missing optional fields, misspelled keys. Generating from actual JSON guarantees types match real data structure.
Handle Complex Nested Data: Modern APIs return deeply nested JSON (user → profile → settings → preferences). Manually typing these nested structures is painful and error-prone. This tool recursively generates nested interfaces automatically.
Maintain Types During API Changes: When APIs evolve (new fields, changed types), paste updated JSON response to regenerate interfaces. Compare with existing types to catch breaking changes before runtime errors occur.
Compile-Time Safety: TypeScript catches type errors during development. Access non-existent property or use wrong type, TypeScript errors prevent bugs before running code.
IntelliSense Autocomplete: IDEs (VS Code, WebStorm) provide autocomplete, type hints, and inline documentation based on interfaces. Improves developer experience and reduces lookups.
Refactoring Confidence: Rename properties or change types with confidence. TypeScript shows every affected location. No runtime surprises from missed updates.
Documentation: Interfaces serve as living documentation of data structures. New team members understand API response shapes by reading interfaces.
Generate types for REST API responses (fetch user data, product lists, search results). Create interfaces for GraphQL query results. Define types for database query results (MongoDB documents, SQL rows). Type configuration files loaded as JSON. Type-safe Redux state or React Query responses.
This tool handles nested objects, arrays (infers element types), optional vs required properties, union types (string | null), primitive types (string, number, boolean, null), and generates valid TypeScript identifiers from JSON keys. All processing happens client-side using TypeScript AST generation.
How developers use JSON to TypeScript
Generate TypeScript interfaces for REST API responses to enable type-safe API calls. Fetch example response, generate interface, use in typed API client functions. Catch API contract violations at compile time.
Generate TypeScript types for Redux state structures. Define state shape as JSON, generate interface, use in reducers and selectors for type-safe state management. Prevent state mutation bugs.
Generate TypeScript interfaces for MongoDB document schemas. Query MongoDB, get example document, generate interface for type-safe document operations with Mongoose or native driver.
Generate TypeScript types for GraphQL query results. Execute query in GraphQL playground, copy result JSON, generate interface. Use in React Query, Apollo Client, or urql for type-safe GraphQL development.
Master TypeScript interface generation
This tool provides instant TypeScript interface generation from JSON with intelligent type inference, nested structure handling, and configurable output options. All processing happens client-side using TypeScript AST generation libraries.
Paste valid JSON representing your data structure. The tool analyzes types: strings become string, numbers become number, booleans become boolean, null becomes null (or string | null if you want nullable types). Arrays infer element types from first element or use any[] for empty arrays.
Choose interface syntax (interface User {}) or type alias (type User = {}). Interfaces are preferred for object shapes in TypeScript best practices. Type aliases work for unions, intersections, or when you prefer = syntax. Both produce identical runtime behavior.
Enable "Optional Properties" to mark all fields with ? making them optional. Useful when API responses have inconsistent fields or optional data. Disable for strict required properties matching JSON exactly.
Nested JSON objects generate nested interface definitions. You can configure to extract nested objects as separate named interfaces or inline them. Separate interfaces improve reusability (UserProfile interface used in multiple places).
Arrays infer element types from first array element. ["a", "b"] becomes string[]. [{id: 1}, {id: 2}] generates object interface then Array<ObjectInterface>. Empty arrays [] default to any[] - manually refine to specific type.
JSON keys can be any string including spaces, hyphens, special chars. TypeScript identifiers have restrictions. Tool automatically converts invalid names: "first-name" → "firstName", "user id" → "userId", preserving semantics while ensuring valid TypeScript.
Everything you need to know
Your data never leaves your browser
Your JSON data never leaves your browser. This converter operates entirely client-side using JavaScript JSON parsing and TypeScript AST generation. Zero server uploads, zero data transmission, zero logging.
Safe for generating types from sensitive API responses, customer data, financial records, healthcare data (HIPAA), payment information (PCI-DSS), or any proprietary data structures. Use with confidence for production APIs or confidential data.
Performance metrics